A new laminar flow, high speed, 300,000 cells per minute, combined potential sensing Coulter type and optical transducer, The AMAC IV, which will permit simultaneous electronic cell volume, fluorescence and light scattering measurments has been constructed. This transducer is the second stage of a proposed Automated Multiparameter Analyzer for Cells, the AMAC. The pulse generated by the cell traversing the Coulter orifice besides providing the first parameter of the proposed system also serves to flash an argon ion laser, the light source for fluorescence and light scattering measurments on the cell. The utilization of the new effectively windowless flow chamber, AMAC IV or square orifice AMAC III will permit combined electronic cell volume and optical measurements. All of these measurements will be rapidly, less than 10 microseconds, inputed into the computer by a special multiplexer and subsequently batch processed. Initial studies of the light scattering will be performed utilizng a pulsed laser to determine the optimal configuration for the final detector. The AMAC will be programmed with purified cells which have previously been separated by BSA gradient and unity gravity sedimentation and microscopically analyzed from fixed stained dispersions produced with the Centrifugal Cytology bucket. After the AMAC is programmed, parallel pairs of samples will be analyzed by the Cytology Staff of PCRI and the AMAC. The Centrifugal Cytology rotor is to be utilized to obtain a statistically valid test of PAPette samples and to develop methodology for sputum, urine and other exfoliated cells. Plaque Cytogram assays are to be utilized to identify classes of blood lymphocytes and means developed to non-selectively increase the concentration of blood leukocytes in order to be able to have the AMAC also serve as a sophisticated leukocyte analyzer.